Effective Changes in Microbial Diversity of Activated Sludge Consortium in Presence of Benzene, Toluene & Xylene


Jordan Brianna, Taylor Connor

Activated sludge was adapted sequentially to benzene, toluene and o-xylene to study the effects on the change in the microbial community. Sludge suitable for benzene, toluene and o-xylene each degraded separately by different levels in a following order; toluene> o-xylene> benzene. Degradation rates were increased after exposure to points or repeated substrates. Eleven types of sludge were prepared by the benzene, toluene and o-xylene combination or sequential adaptations. Analysis of the concentration revealed that the acclimated sludge had different characteristics from non acclimated sludge and could be grouped according to their prior treatment. The sludge profile was affected by the final point of the substrate adaptation irrespective of the sequence adaptive tracking. In the sludge, adapted to 50 ppm toluene, Nitrosomonas sp. and bacteria were dominated, but these bands were not dominant in benzene and benzene and after toluene adaptations. Instead, Flexibacter sp. was dominant in these cultures. Dechloromona ssp was dominant in culture adapted to 50 ppm benzene. Thauerasp. was the main band in the sludge adapted to 50 ppmxylene, but became vaguer as the concentration of xylene was increased. Instead, Flexibacter sp. dominated in the sludge adapted to 100 ppm xylene, but not in the culture adapted to 250 ppm xylene. Two bacterial species dominated in sludge suitable for 250 ppm xylene, and they also existed in the slurry suitable to achieve 250 ppm xylene, toluene and benzene.

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